pre-scheduled posts - posts can be scheduled to go live ahead of time which is great if you know you're going to be busy or away from the internet
Geography studies - these two teachers created ficitonal characters who blogged about their travels around the world and asked the students to map the places they were writing from. The students posted comments / answers as a class.
Which tools to use? It depends on the job!
For exampleComparison of wikis, Moodle, & blogs
Blogs
Wikis
Google Docs
YouTube / KeepVid
Voicethread
Podcasting
Flip cameras
Moodle / Blackboard / etc.
Student response systems
Media Specialist